1. Field of the Invention
This invention relates generally to a composition which employs a unique explosive filler, preferably of fine particle size, either predominantly or exclusively to insure minimal critical thickness for detonation. Replacing a portion of the explosive filler with an energetic, compatible plasticizer diluent provides castability at moderate temperatures while maintaining the required high rates of detonation and effecting a crosslinked polymeric network under mild curing conditions to eliminate undesirable thermoplasticity.
2. Description of the Prior Art
There are a limited number of alternative high explosive compositions that are readily processable, safe to handle, have appropriate high rates of detonation, suitable low critical thickness propagation and with the specific physical properties to qualify as flexible sheet explosives. Of the explosives that qualify or meet the requirements, such as the Military Specification (MIL Spec.), the most widely known of these compositions are those designated as "Deta Sheet", extrudable compositions containing 63 - 75% pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX) or cyclotetramethylene tetranitramine (HMX) in a plasticized elastomeric binder. All of the aforementioned compositions are referred to hereinafter as PETN, RDX, and HMX, respectively.
Qualified sheet explosives are unique in their own right because they fulfill certain needs that cannot readily be met by other kinds of explosive materials. They are sturdy, durable, have uniform detonation velocity and a high degree of safety. Moreover, they are waterproof, insensitive to shock, easy to cut into any desired shape and easily applied. Among the more widely known applications are their use in metal cutting, hardening, general demolition, and safe-arm devices.
Explosive compositions which presently are used in applications requiring flexible sheet have certain inherent shortcomings. Generally, these fall into the following categories. The fabrication techniques are limited to extrusion because of the thermoplastic nature of the binder; the binder thermoplasticity limits the temperature of potential application or use; and the relatively low explosive filler concentration ordinarily required to provide castable systems reduces the detonation rate and/or increases the critical thickness required for detonation propagation.